<!-- borrowed from Nuxt! -->

<template>
    <div class="progress" :style="{
    'width': percent+'%',
    'height': height,
    'background-color': canSuccess? color : failedColor,
    'opacity': show ? 1 : 0
  }"></div>
</template>

<script>
  export default {
    data() {
      return {
        percent: 0,
        show: false,
        canSuccess: true,
        duration: 3000,
        height: '2px',
        color: '#ffca2b',
        failedColor: '#ff0000',
      }
    },
    methods: {
      start() {
        this.show = true
        this.canSuccess = true
        if (this._timer) {
          clearInterval(this._timer)
          this.percent = 0
        }
        this._cut = 10000 / Math.floor(this.duration)
        this._timer = setInterval(() => {
          this.increase(this._cut * Math.random())
          if (this.percent > 95) {
            this.finish()
          }
        }, 100)
        return this
      },
      set(num) {
        this.show = true
        this.canSuccess = true
        this.percent = Math.floor(num)
        return this
      },
      get() {
        return Math.floor(this.percent)
      },
      increase(num) {
        this.percent = this.percent + Math.floor(num)
        return this
      },
      decrease(num) {
        this.percent = this.percent - Math.floor(num)
        return this
      },
      finish() {
        this.percent = 100
        this.hide()
        return this
      },
      pause() {
        clearInterval(this._timer)
        return this
      },
      hide() {
        clearInterval(this._timer)
        this._timer = null
        setTimeout(() => {
          this.show = false
          this.$nextTick(() => {
            setTimeout(() => {
              this.percent = 0
            }, 200)
          })
        }, 500)
        return this
      },
      fail() {
        this.canSuccess = false
        return this
      }
    }
  }
</script>

<style scoped>
    .progress {
        position: fixed;
        top: 0px;
        left: 0px;
        right: 0px;
        height: 2px;
        width: 0%;
        transition: width 0.2s, opacity 0.4s;
        opacity: 1;
        background-color: #efc14e;
        z-index: 999999;
    }
</style>
